#!/bin/bash
set -euo pipefail

BASE="/opt"
CURRENT="/opt/iventoy"

PERSIST="/srv/iventoy"
ISO_DIR="${PERSIST}/iso"
CONFIG_DIR="${PERSIST}/config"
CONFIG_FILE="${CONFIG_DIR}/config.dat"

SERVICE="iventoy"

TMP="/tmp/iventoy-update"
GITHUB_REPO="ventoy/PXE"

MAX_BACKUPS=10

echo "=========================================="
echo " iVentoy Update"
echo "=========================================="
echo

# --------------------------------------------------
# Root check
# --------------------------------------------------

if [ "$(id -u)" -ne 0 ]; then
    echo "ERROR: Dieses Script muss als root laufen."
    exit 1
fi

# --------------------------------------------------
# Dependencies
# --------------------------------------------------

apt-get update -qq
apt-get install -y -qq curl tar >/dev/null

# --------------------------------------------------
# Persistent directories
# --------------------------------------------------

mkdir -p "$ISO_DIR"
mkdir -p "$CONFIG_DIR"

# --------------------------------------------------
# Latest Version ermitteln
# --------------------------------------------------

echo "Ermittle aktuelle iVentoy-Version..."

LATEST_TAG=$(
    curl -fsSL \
        -o /dev/null \
        -w '%{url_effective}' \
        "https://github.com/${GITHUB_REPO}/releases/latest" \
    | awk -F/ '{print $NF}'
)

VERSION="${LATEST_TAG#v}"

if [ -z "$VERSION" ]; then
    echo "ERROR: Konnte aktuelle Version nicht ermitteln."
    exit 1
fi

TARGET="${BASE}/iventoy-${VERSION}"

echo "Neueste Version: $VERSION"

# --------------------------------------------------
# Prüfen ob bereits aktuell
# --------------------------------------------------

if [ -L "$CURRENT" ]; then
    CURRENT_TARGET=$(readlink -f "$CURRENT" || true)

    if [ "$CURRENT_TARGET" = "$TARGET" ]; then
        echo
        echo "=========================================="
        echo " iVentoy ist bereits aktuell"
        echo "=========================================="
        echo
        echo "Aktive Version: $VERSION"
        echo "Installation:   $CURRENT -> $TARGET"
        echo
        exit 0
    fi
fi

# --------------------------------------------------
# Bestehende Config übernehmen
# --------------------------------------------------

if [ ! -f "$CONFIG_FILE" ]; then

    if [ -f "${CURRENT}/data/config.dat" ]; then
        echo
        echo "Übernehme bestehende iVentoy Config..."
        cp -a "${CURRENT}/data/config.dat" "$CONFIG_FILE"
    else
        echo
        echo "WARNUNG: Keine bestehende config.dat gefunden."
    fi

fi

# --------------------------------------------------
# Config Backup
# --------------------------------------------------

if [ -f "$CONFIG_FILE" ]; then

    BACKUP="${CONFIG_FILE}.bak-$(date +%Y%m%d-%H%M%S)"

    echo
    echo "Sichere Config:"
    echo "  $BACKUP"

    cp -a "$CONFIG_FILE" "$BACKUP"

    # --------------------------------------------------
    # Backup Rotation
    # --------------------------------------------------

    echo "Behalte maximal ${MAX_BACKUPS} Config-Backups..."

    find "$CONFIG_DIR" \
        -maxdepth 1 \
        -type f \
        -name 'config.dat.bak-*' \
        -printf '%T@ %p\n' \
        | sort -nr \
        | tail -n +"$((MAX_BACKUPS + 1))" \
        | cut -d' ' -f2- \
        | xargs -r rm -f
fi

# --------------------------------------------------
# Download / Entpacken
# --------------------------------------------------

if [ -d "$TARGET" ]; then

    echo
    echo "Version $VERSION ist bereits vorhanden:"
    echo "  $TARGET"

else

    rm -rf "$TMP"
    mkdir -p "$TMP"

    ARCHIVE="iventoy-${VERSION}-linux-x86_64-free.tar.gz"
    URL="https://github.com/${GITHUB_REPO}/releases/download/v${VERSION}/${ARCHIVE}"

    echo
    echo "Lade herunter:"
    echo "  $URL"

    curl -fL "$URL" -o "${TMP}/${ARCHIVE}"

    echo
    echo "Entpacke iVentoy..."

    tar -xzf "${TMP}/${ARCHIVE}" -C "$TMP"

    EXTRACTED="${TMP}/iventoy-${VERSION}"

    if [ ! -d "$EXTRACTED" ]; then
        echo "ERROR: Erwartetes Verzeichnis wurde nicht gefunden:"
        echo "  $EXTRACTED"
        exit 1
    fi

    mv "$EXTRACTED" "$TARGET"

fi

# --------------------------------------------------
# ISO Symlink
# --------------------------------------------------

echo
echo "Setze ISO-Symlink..."

rm -rf "${TARGET}/iso"
ln -s "$ISO_DIR" "${TARGET}/iso"

# --------------------------------------------------
# Config Symlink
# --------------------------------------------------

if [ -f "$CONFIG_FILE" ]; then

    echo "Setze Config-Symlink..."

    rm -f "${TARGET}/data/config.dat"
    ln -s "$CONFIG_FILE" "${TARGET}/data/config.dat"

fi

# --------------------------------------------------
# Service stoppen
# --------------------------------------------------

echo
echo "Stoppe iVentoy..."

systemctl stop "$SERVICE" 2>/dev/null || true

sleep 2

# --------------------------------------------------
# Alte direkte Installation sichern
# --------------------------------------------------

if [ -e "$CURRENT" ] && [ ! -L "$CURRENT" ]; then

    OLD="${BASE}/iventoy-old-$(date +%Y%m%d-%H%M%S)"

    echo
    echo "Bestehende Installation wird verschoben:"
    echo "  $CURRENT -> $OLD"

    mv "$CURRENT" "$OLD"

fi

# --------------------------------------------------
# Current Symlink atomar setzen
# --------------------------------------------------

echo
echo "Aktiviere iVentoy $VERSION..."

ln -sfn "$TARGET" "${CURRENT}.new"
mv -Tf "${CURRENT}.new" "$CURRENT"

# --------------------------------------------------
# Service starten
# --------------------------------------------------

echo
echo "Starte iVentoy..."

systemctl start "$SERVICE"

sleep 3

# --------------------------------------------------
# Health Check
# --------------------------------------------------

FAILED=0

if ! systemctl is-active --quiet "$SERVICE"; then
    echo "ERROR: systemd Service läuft nicht."
    FAILED=1
fi

if ! ss -lntH | awk '{print $4}' | grep -Eq '[:.]26000$'; then
    echo "ERROR: TCP 26000 lauscht nicht."
    FAILED=1
fi

if ! ss -lntH | awk '{print $4}' | grep -Eq '[:.]16000$'; then
    echo "ERROR: TCP 16000 lauscht nicht."
    FAILED=1
fi

if ! ss -lnuH | awk '{print $4}' | grep -Eq '[:.]69$'; then
    echo "ERROR: UDP 69 lauscht nicht."
    FAILED=1
fi

if ! ss -lnuH | awk '{print $4}' | grep -Eq '[:.]4011$'; then
    echo "ERROR: UDP 4011 lauscht nicht."
    FAILED=1
fi

if ! ss -lnuH | awk '{print $4}' | grep -Eq '[:.]67$'; then
    echo "ERROR: UDP 67 lauscht nicht."
    FAILED=1
fi

if [ "$FAILED" -ne 0 ]; then

    echo
    echo "=========================================="
    echo " UPDATE FEHLGESCHLAGEN"
    echo "=========================================="
    echo

    if [ -f "${CURRENT}/log/log.txt" ]; then
        echo "Letzte iVentoy Log-Einträge:"
        tail -n 40 "${CURRENT}/log/log.txt" || true
    fi

    exit 1
fi

# --------------------------------------------------
# Cleanup
# --------------------------------------------------

rm -rf "$TMP"

echo
echo "=========================================="
echo " Update erfolgreich"
echo "=========================================="
echo
echo "Aktive Version:"
echo "  $VERSION"
echo
echo "Installation:"
echo "  $CURRENT -> $TARGET"
echo
echo "Config:"
echo "  ${CURRENT}/data/config.dat -> $CONFIG_FILE"
echo
echo "ISO:"
echo "  ${CURRENT}/iso -> $ISO_DIR"
echo
echo "Config-Backups:"
echo "  maximal $MAX_BACKUPS"
echo